A well know method for detecting leaks in air conditioning and refrigeration systems is to inject a fluorescent dye into the system. Wherever there is a leak, the dye will leak out with the refrigerant and oil and can be detected by shining a light of an appropriate wavelength, typically ultraviolet or near ultraviolet, on the area.
This method has been used at least since the Montreal Protocol of 1987 was adopted. Its use increased substantially after R134A refrigerant became widely used in 1993. R134A molecules are smaller than those of previous refrigerants. Systems used R134A refrigerant also operate under higher pressures. This combination resulted in a greater number of leaks of smaller size. It was, and continues to be, a significant problem.
Since about 1995 fluorescent leak detection has been acknowledged as the best method of detecting such leaks. Previously, systems that leaked were generally “topped up” with additional refrigerant. In most jurisdictions this is now illegal. Even though there are millions of injectors in circulation, the actual use of fluorescent leak detection has been held back, at least in part, because it is very messy.
Alternative leak detection methods include, for example, soap and water, non-fluorescent dye and electronic sniffers. Soap and water is largely ineffective as it is hard to control its application to defined areas and it does not detect very small leaks that might involve, perhaps an ounce of refrigerant per year. This is significant when some new cars only have 1 lb. of refrigerant in a properly operating system. The use of non-fluorescent dye generally suffers from the same difficulties as fluorescent dye, and non-fluorescent dyes are generally not as effective visual indicators of leaks. Sniffers are very useful in leak detection. In fact, they are often used as a complementary method to fluorescent leak defection. Sniffers are very good at finding leaks leading to the evaporator. This can be done with dye, but is not usually as effective. Sniffers do need to be close to the leak to obtain a sniff. This can be difficult when the area is inaccessible. For most leaks it will be more effective to inject dye, leave and return later to detect any leaks.
There are many forms of dye injectors currently in use including the Cliplight™ Revolver™ sold by Cliplight Manufacturing Company of Toronto Canada and described in co-pending International patent application no. PCT/CA2004/000114 filed 29 Jan. 2004 under title Manual Liquid Metering Device and Cartridge claiming the benefit of U.S. Provisional Patent Application Ser. No. 60/443,532 filed 30 Jan. 2003.
All of the injectors currently in use suffer from one common problem. They are all very messy to store. During use, the injector is connected to a fitting on the system and dye is pumped into the system thru the fitting. When the injector is disconnected from the system there is dye remaining in the fitting on the injector. This dye will drip out of the fitting during storage and contaminate anything near it. Due to its nature, this dye permeates most materials and will permanently stain. When the dye leaks out it gets on the exterior of the fitting and the dye injector making the device very messy from that point on. Also, upon connection to the next system port the dye remaining in the dye injector fitting will contaminate the exterior of the port, leaving a mess on that port even before use. Also, residual dye build up can be sufficient to create particles that can be introduced into the system with adverse consequences.
Plugs and caps have been tried to contain the dye remaining in the injector fitting. Plugs that go inside the fitting displace some of the dye when installed, but the remaining dye leaks out during storage or pours out when the plug is removed and still contaminates the next system port. Caps, such as vinyl-dipped caps, that go over the outside of the injector fitting attempt to contain the dye in the fitting. Because this dye is so aggressive, it will eventually leak out from under the cap. Any remaining dye under the cap will also pour out when the cap is removed and also contaminate the exterior of the next system port.
Such caps have to be constantly cleaned, typically with a rag, to avoid contamination from one fitting to the next, or between uses on the same fitting. The dye tends to migrate externally on the fitting over time and the rag becomes contaminated. Often the injector is simply hung up after use to allow the dye to drip into a bucket. These problems can be exacerbated in mobile use where the injector cannot be hungup after use.
As leaking refrigerant is harmful to the environment and fluorescent leak detection is generally the most effective manner of leak detection, limitations on the use of fluorescent leak detection are themselves an environmental problem.
All of the various devices designed to contain the dye within the injector fitting do not work very well. At best they reduce the mess or delay the mess until later.